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491.
Yan Xu Dr. Yuta Suzuki Makoto Komiyama Prof. 《Angewandte Chemie (International ed. in English)》2009,48(18):3281-3284
A trap that closes with a “click” : The copper‐catalyzed azide–alkyne cycloaddition can occur in different G‐quadruplex structures (see scheme). The species trapped by the click reaction can then be separated and analyzed. By using this approach, a DNA–RNA hybrid‐type G‐quadruplex structure formed by human telomeric DNA and RNA sequences was detected.
492.
Yuta Suzuki Ryo Yazaki Naoya Kumagai Dr. Masakatsu Shibasaki Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(27):5026-5029
Taking the reins : The title transformation of thioamides and N‐diphenylphosphinoyl imines is described. By harnessing the power of cooperative catalysis between a soft Lewis acid and a hard Brønsted base, thioamide carbon pronucleophiles can furnish Mannich products (see scheme). Divergent transformation of the thioamide functionality highlights the utility of this methodology.
493.
Yuji Matsuya Dr. Yuta Kobayashi Takanori Kawaguchi Ayana Hori Yuka Watanabe Kentaro Ishihara Kanwal Ahmed Zheng‐Li Wei Da‐Yong Yu Qing‐Li Zhao Takashi Kondo Prof. Dr. Hideo Nemoto Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(23):5799-5813
A drug of two halves : New artificial compounds composed of a macrosphelide core skeleton and an epothilone side chain were designed and synthesized. These compounds were more potent inducers of apoptosis than the parent natural‐type macrosphelides.
494.
C5–C10 Directly Bonded Tetrodotoxin Analogues: Possible Biosynthetic Precursors of Tetrodotoxin From Newts 下载免费PDF全文
Yuta Kudo Yoko Yamashita Prof. Dr. Dietrich Mebs Dr. Yuko Cho Prof. Dr. Keiichi Konoki Prof. Dr. Takeshi Yasumoto Prof. Dr. Mari Yotsu‐Yamashita 《Angewandte Chemie (International ed. in English)》2014,53(52):14546-14549
The identification of novel tetrodotoxin (TTX, 1 ) analogues would significantly contribute to the elucidation of its biosynthetic pathway. In this study, the first C5–C10 directly bonded TTX analogues, 4,9‐anhydro‐10‐hemiketal‐5‐deoxyTTX ( 2 ) and 4,9‐anhydro‐8‐epi‐10‐hemiketal‐5,6,11‐trideoxyTTX ( 3 ), were found in the newt Cynops ensicauda popei by using a screening method involving HILIC‐LC–MS/MS focused on the fragment ions of TTX analogues, and their structures were elucidated by spectroscopic methods. Compound 2 was detected in a wide range of newt species, and the 2 and TTX contents of 22 newt specimens were correlated (rs=0.88). Based on these results and its structural features, 2 was predicted to serve as a precursor of TTX that would be directly converted into 4,9‐anhydroTTX ( 4 ) by Baeyer–Villiger‐like oxidation or via 4,9‐anhydro‐5‐deoxyTTX formed by cleavage of the C5–C10 bond. The bicyclic carbon skeletons of 2 and 3 suggested a possible monoterpene origin for TTX. 相似文献
495.
Prof. Dr. Kenshu Fujiwara Yuki Suzuki Nao Koseki Yu‐ichi Aki Yuta Kikuchi Shun‐ichi Murata Fuyuki Yamamoto Mariko Kawamura Prof. Dr. Toshio Norikura Prof. Dr. Hajime Matsue Prof. Dr. Akio Murai Prof. Dr. Ryo Katoono Prof. Dr. Hidetoshi Kawai Prof. Dr. Takanori Suzuki 《Angewandte Chemie (International ed. in English)》2014,53(3):780-784
Pectenotoxin‐2 (PTX2) is a shellfish toxin and has a non‐anomeric spiroacetal, which is not stabilized by an anomeric effect. The selective construction of the non‐anomeric spiroacetal has been a major problem in the synthesis of PTX2. Described herein is the stereoselective total synthesis of PTX2 via the isomerization of anomeric spiroacetal pectenotoxin‐2b (PTX2b). The synthesis of PTX2b was achieved by a simple process including sulfone‐mediated assembly of spirocyclic and bicyclic acetals and subsequent macrocyclization by ring‐closing olefin metathesis. Finally, the selective construction of PTX2 was accomplished by the early termination of a dynamic transition process to equilibrium in the acid‐catalyzed isomerization of anomeric PTX2b. [6,6]‐Spiroacetal pectenotoxin‐2c (PTX2c) was also synthesized from PTX2b. The cytotoxicity assay of the synthetic compounds against HepG2 and Caco2 cancer cells showed a potency of the order: PTX2?PTX2b>PTX2c. 相似文献
496.
Yuta Saito Takahito Kawano Masatsugu Shimomura Hiroshi Yabu 《Macromolecular rapid communications》2013,34(8):630-634
Porous surface patterns are used in a wide variety of practical applications. Honeycomb‐patterned porous polymer films are good templates for preparing porous surfaces due to their simple fabrication and the arrangement of pores on the surface. Catechol groups include in adhesive protein of mussels have attracted much attention due to their highly and substrate‐independent adhesive properties. In this paper, highly and substrate‐independent adhesive honeycomb‐patterned porous polymer films are prepared by using amphiphilic copolymer having catechol moieties. Furthermore, porous surface patterns are transferred on various organic or inorganic substrates by wet etching with using adhesive honeycomb films as templates.
497.
Prof. Dr. Naoki Kanoh Shunya Itoh Kohei Fujita Dr. Kohei Sakanishi Ryosuke Sugiyama Yuta Terajima Prof. Dr. Yoshiharu Iwabuchi Prof. Dr. Shinichi Nishimura Prof. Dr. Hideaki Kakeya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(25):8586-8595
Heronamides are biosynthetically related metabolites isolated from marine‐derived actinomycetes. Heronamide C shows potent antifungal activity by targeting membrane phospholipids possessing saturated hydrocarbon chains with as‐yet‐unrevealed modes of action. In spite of their curious hypothesized biosynthesis and fascinating biological activities, there have been conflicts in regard to the reported stereochemistries of heronamides. Here, we describe the asymmetric total synthesis of the originally proposed and revised structures of heronamide C, which unambiguously confirmed the chemical structure of this molecule. We also demonstrated nonenzymatic synthesis of heronamides A and B from heronamide C, which not only proved the postulated biosynthesis, but also confirmed the correct structures of heronamides A and B. Investigation of the structure–activity relationship of synthetic and natural heronamides revealed the importance of both long‐range stereochemical communication and the 20‐membered macrolactam ring for the biological activity of these compounds. 相似文献
498.
Dr. Shigeo Yasuda Yasuaki Kawaguchi Yuta Okamoto Prof. Dr. Chisato Mukai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):12181-12188
A highly chemo‐ and regioselective partially intramolecular rhodium(I)‐catalyzed [2+2+2] cycloaddition of allenynes with alkynes is described. A range of diverse polysubstituted benzene derivatives could be synthesized in good to excellent yields, in which the allenynes served as synthetic equivalent to the diynes. A high regioselectivity could be observed when allenynes were treated with unsymmetrical alkynes. 相似文献
499.
Dr. Yuta Maki Kazuki Kawata Dr. Yanbo Liu Kang-Ying Goo Dr. Ryo Okamoto Prof. Dr. Yasuhiro Kajihara Dr. Ayano Satoh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(37):e202201253
Glycosylation of proteins is known to be essential for changing biological activity and stability of glycoproteins on the cell surfaces and in body fluids. Delivering of homogeneous glycoproteins into the endoplasmic reticulum (ER) and the Golgi apparatus would enable us to investigate the function of asparagine-linked (N-) glycans in the organelles. In this work, we designed and synthesized an intentionally glycosylated cholera toxin B-subunit (CTB) to be transported to the organelles of mammalian cells. The heptasaccharide, the intermediate structure of various complex-type N-glycans, was introduced to the CTB. The synthesized monomeric glycosyl-CTB successfully entered mammalian cells and was transported to the Golgi and the ER, suggesting the potential use of synthetic CTB to deliver and investigate the functions of homogeneous N-glycans in specific organelles of living cells. 相似文献
500.
Hanjun Zhao Prof. Dr. Yuta Takano Dr. Devika Sasikumar Dr. Yukiko Miyatake Prof. Dr. Vasudevanpillai Biju 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(71):e202202014
The present study provides design guidance for unique multipotent molecules that sense and generate singlet oxygen (1O2). A rhodamine 6G-aminomethylanthracene-linked donor-acceptor molecule ( RA ) is designed and synthesized for demonstrating wavelength-dependent functionalities as follows; (i) RA acts as a conventional fluorogenic 1O2 sensor molecule like the commercially available reagent, singlet oxygen sensor green (SOSG), when it absorbs ultraviolet (UV)-visible light and reacts with 1O2. (ii) RA acts as a temporally controlled 1O2 sensing reagent under the longer wavelength (∼700 nm) photosensitization. RA enters an intermediate state after capturing 1O2 and does not become strongly fluorescent until it is exposed to UV, blue, or green light. (iii) RA acts as an efficient photosensitizer to generate 1O2 under green light illumination. The spin-orbit charge transfer mediated intersystem crossing (SOCT-ISC) process achieves this function, and RA shows a potential cancer-killing effect on pancreatic cancer cells. The wavelength-switchable functionalities in RA offer to promise molecular tools to apply 1O2 in a spatiotemporal manner. 相似文献